Biodiversity (or biological diversity) is the variety of all life forms on earth - the different plants, animals and micro-organisms, the genes they contain, and the ecosystems of which they form a part. Biodiversity is constantly changing. It is increased by genetic change and evolution and is reduced by processes such as habitat degradation and species extinction.

Australia's biodiversity is unique and globally significant, with Australia being home to many endemic plants and animals, that is, they are found nowhere else in the world. Australia is recognised as one of only 17 'mega-diverse' countries, with ecosystems of exceptional variety and uniqueness. This group of mega-diverse countries covers less than 10% of the global surface, but supports more than 70% of the earth's biological diversity.

Loss of biodiversity is considered by some as Australia's most serious environmental problem. Habitat degradation resulting from human activity has put many unique species at risk. The clearance of native vegetation is a significant threat to terrestrial biodiversity. Other threats to biodiversity include deterioration of soil and water quality, increased dryland salinity, the spread of weeds and feral pests and climate change. Although land clearing has continued since 1990, the rate of forest land conversion decreased by more than one-third or 182.6 thousand hectares (graph 3.1). The figures do not distinguish between the clearance of native or non-native vegetation.

3.1 Land use change: Forest conversion and reclearing

Threatened species

The Australian Government administers biodiversity conservation through the Environment Protection and Biodiversity Conservation Act 1999 (Cwlth) (EPBC Act). This environmental legislation provides a framework and advice to protect and manage important flora, fauna, ecological communities and heritage places. The EPBC Act classifies listed threatened species into six categories: extinct; extinct in the wild; critically endangered; endangered; vulnerable; and conservation dependent.

Since the introduction of the EPBC Act, the number of listed threatened fauna has increased by 35% from 315 to 426. In September 2009, nearly half of the 120 mammals listed as threatened were classified as vulnerable, almost a third were more seriously threatened (endangered and critically endangered) and the remainder were presumed extinct. The number of endangered fauna species rose by 41% between 2000 and 2009 and the number of vulnerable fauna species increased by 20% over this period (graph 3.2). However, these increases may reflect taxonomic revisions and improved reporting in conservation status and do not necessarily mean a change in the conservation status of the fauna.

Table 3.3 shows that in 2009, 104 species of Australian flora and fauna were listed as extinct, and 1,643 species and 46 ecological communities were listed as endangered or vulnerable under the EPBC Act. An ecological community is a naturally occurring and unique group of plants and animals.

Although Australia's biodiversity continues to be threatened by many factors, measures have been put in place to protect native flora and fauna. One such measure is a system of protected areas (the Natural Reserve System) that is dedicated to the protection and maintenance of biological diversity and of natural and cultural resources. The development of a comprehensive, adequate and representative National Reserve System is the responsibility of the Commonwealth, state and territory governments as part of Australia's obligation under the United Nations Biodiversity Convention established in 1993.

Most national parks and other protected areas in Australia are declared and managed by state and territory governments, although some protected areas are managed by conservation or other groups. Declaration and management of Indigenous Protected Areas - Indigenous-owned land that is managed to protect its natural and associated cultural values - began in 1998.

The area of conservation reserves in each state and territory is recorded in the Collaborative Australian Protected Areas Database (CAPAD) using the World Conservation Union (IUCN) classification system of protected areas. The classification system comprises seven categories based on the main (or primary) management intent of protected areas.

From 2004 to 2006, Australia's terrestrial protected areas increased by more than 8.6 million hectares and now extend across 89.5 million hectares or 12% of Australia. Table 3.4 shows the area of protected land in each category in 2006. Included in the 89.5 million hectares is 14.6 million hectares of Indigenous Protected Areas. These areas are actively managed by the Indigenous owners and rangers also work to protect biodiversity by controlling weeds, feral animals and bushfires along with visitor impacts, for all Australians.

Source: Department of the Environment, Water, Heritage and the Arts, CAPAD, last viewed September 2009

The area protected for National Parks (category II) has increased by over 7 million hectares between 2002 and 2006 and now encompasses almost 5% of the total land area of Australia. (graph 3.5).

3.5 Protected Areas, as a percentage of Australia - 2002-2006

The Australian Government's Caring for our Country program aims to expand the area protected within the National Reserve System to at least 125 million hectares by 2013 and expand Indigenous Protected Areas by between 8 and 16 million hectares. In addition, the programs aim to increase native habitat by at least one million hectares and reduce the impact of cane toads, camels, rodents, rabbits and weeds.

An invasive species is a non-indigenous species with an adverse impact on the habitats that it invades. Invasive species threaten valued environmental, agricultural or other social resources through the damage they cause. Invasive species include feral animals, marine pests, weeds, non-native insects and other invertebrates, and diseases and parasites. These species can threaten native species, contribute to land degradation and reduce agricultural productivity.

The cost of weeds to Australian agriculture (impact and control costs) has been estimated at more than $3.4 billion (b) annually (Caring for our Country, Business Plan 2009-2010). ABS data for 2006-07 show that farmers spent $1.6 b controlling and preventing weeds, which was more than for pests ($768 million (m)) and land and soil problems ($649 m) combined (see graph 3.6). Weed management activities also proved the most time consuming with agricultural businesses undertaking, on average, 31 person days of effort on these activities. In comparison, 26 and 23 days were spent on managing pests and land and soil problems, respectively.

Weeds of National Significance is an agreed list of 20 problem weeds used as a guide for a coordinated national effort for addressing weed problems (see table 3.7). Selection of these species was made by the Australian government and all state and territory governments in 1999 based on environmental damage and economic impacts.

In Australia, the annual cost of pest species has been estimated at around $720 million (Counting the Cost, 2004). Some invasive animals or pests were deliberately introduced to Australia, while others were accidentally imported. Table 3.8 lists the major pest species of concern which have been introduced into Australia.

The cane toad is an example of an introduced feral animal. It was introduced into Australia as a biological control against cane beetles that destroy sugarcane crops, but failed to control the cane beetles and became a major pest itself. Cane toads eat mainly insects, but also frogs, small mammals and snakes. Additionally, because they are poisonous, cane toads kill many animals that prey on them including goannas, quolls and birds. They are still spreading across Australia, continuing to migrate both west and south.